Valorisation of Mining Waste for Gold Recovery (original) (raw)

2018

Purpose: the metals and industrial minerals contained in the tailings produced by mining and quarrying activities, are cause of environmental damage. The objective of this experimental work is the application of innovative technologies for the treatment and exploitation of mining tailings in Romania, in order to recover materials high grade raw to be placed on the market, reducing the volume of the wastes. Further objective, is to optimize some parameters relating to the dissolution of gold and the subsequent recovery from purified solutions, determining beforehand the technical feasibility of the scheme of process developed on a laboratory scale. Methods: the study is focused on hydrometallurgical process for the recovery of gold. The innovative treatment chosen is the thiosulphate process that, compared to conventional cyanide, has several advantages, first of all the most eco-friendly and nontoxic to humans. The conventional process shows operating limits in the case of auriferou...

APPLICATION OF INNOVATIVE PROCESSES FOR GOLD RECOVERY FROM ROMANIAN MINING WASTES

Chemistry Journal of Moldova, 2020

The application of a new hydrometallurgical process for gold extraction by thiosulphate leaching from Romanian mining wastes, coming from Balan and Deva deposits, was studied. Another objective of this work was to develop an integrated flow-sheet including the recycling of process solutions and of the coconut activated carbon used for gold purification. There was obtained 85% of Au extraction after leaching; moreover, an integrated flow-sheet, including recycling of process solution and carbon, was outlined, based on results obtained at a laboratory scale, using a schematic chemical circuit of treatment. Global recovery of the process (leaching-adsorption-desorption-electrodeposition) of about 75-80% of Au was achieved. The developed integrated flow-sheet, allows to recycle the reagents during the process, with a loss of only 5-10%, in particular thiosulphate and alcohol, for each complete circuit of treatment.

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Hydrometallurgical Recovery of Gold from Mining Wastes

2020

Gold is a highly required material for a wide range of personal and industrial applications. The high demand for gold, together with the shortage of natural resources and high pollution potential of wastes generated during mining and ore processing activities led to search for alternative sources of gold. A possible source is represented by mine wastes resulting from the processing of polymetallic or sulfidic ores. The reprocessing of wastes and old tailings with moderate to low content of gold offers not only a business opportunity, but also enhances the quality of the surrounding environment, changes the land use and offers a wide range of socio-economic benefits. Cyanidation, the most widespread Au leaching option, is progressively abandoned due to the high risk associated with its use and to the low public acceptance. Therefore, alternative methods such as thiocyanate, thiourea, thiosulphate and halide leaching gained more and more interest. This chapter presents the most import...

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L.R. Freitas, R.B.E. Trindade and T. Carageorgos THIOSULPHATE LEACHING OF GOLD-COPPER ORES FROM IGARAPE BAHIA MINE (CVRD)

2013

Cyanide is the most used reagent for thc extraction of gold worldwide. lt is a highly effective reagent and suitable for most ores . However, it may not he the case for the so called refractory gold ores, including those of a sulphide matrix, with high copper content and/or carbonaceous matter. Among alternative reagents investigated for gold leaching, thiosulphate seems to he one of lhe most prorrúsing for copper-gold ores. Contrary to cyanide, the process using thiosulphate actually needs some copper present in the ore; olherwise the gold dissolution is not possible. The present work presents basic facts about the chcmistry and thermodynamics of the thiosulphate system for U1e extraction of gold. ln addition, experimental results of a study on lhiosulphate leaching of gold-copper ores from the lgarape Bahia Mine (CVRD, Brazil) are reported. While cyanide should remain as the first choice for lhe hydrometallurgy of most gold ores, lhe results of this study ~ndicate that thiosulphat...

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Methods for Processing Mining Wastes from Copper Extraction for the Recovery of Precious Metals

2019

The tailings pond of the “Central Flotation” Baia Mare, Romania, poses a great ecological problem for the town, surrounding soils and watercourses. The paper reviews the current methods for the processing of the mine tailings. The results of preliminary acid leaching experiments are presented. The leaching carried out in successive steps lead to the significant concentration of the precious metals. The gold contents increased from 0.7 ppm to values 3 times higher in the resulting slime. The slime rich in Au and Ag will be subsequently processed using ionic liquids for a more efficient recovery of the precious metals.

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Ammoniacal thiosulphate leaching of gold ore

2003

Ammoniacal thiosulphate leaching of gold finds a better substitute as it is non-toxic and environmentally safe as compared to the toxic cyanide system for gold extraction. In the present study, an attempt is made to assess the feasibility of ammoniacal thiosulphate leaching of gold ore samples from two different mines namely Akeshi and Hishikari of Japan. In this study, the effect of thiosulphate concentration, effect of ammonia, effect of cupric ions, and few other variables affecting the gold leaching have been studied. The ammoniacal thiosulphate leaching of gold is dependant on both ammonia and thiosulphate concentration. The leaching is improved significantly at a particular ratio of ammonia to thiosulphate concentration and that ratio varies from ore to ore. Copper ions act as an oxidant and the gold dissolution increases substantially in the presence of them. The gold leaching is minimum in the presence of an inert gas such as nitrogen and the leaching increases in presence o...

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